JP5958316B2 - Method for separating and removing aluminum, and method for recovering valuable metals from lithium ion batteries - Google Patents

Description

  The present invention relates to a method for separating and removing aluminum and a method for recovering valuable metals from a lithium ion battery. More specifically, when a positive electrode material having a positive electrode active material fixed to a positive electrode substrate made of an aluminum foil is immersed in a sulfuric acid solution and valuable metals contained in the positive electrode active material are leached and recovered, the aluminum eluted in the sulfuric acid solution The present invention relates to a method for separating and removing aluminum from which lithium is separated and a method for recovering valuable metals from lithium ion batteries to which the method is applied.

  A positive electrode material of a lithium ion battery is obtained by fixing a positive electrode active material such as lithium cobaltate to a positive electrode substrate made of only an aluminum foil. For example, a defective product (manufacturing process scrap) or usage generated in the manufacturing process of the positive electrode material The positive electrode material taken out from the used lithium ion battery contains a lot of valuable materials (valuable metals) to be recovered.

  Conventionally, in order to recover valuable metals from the manufacturing process scrap and used positive electrode material, separation of the positive electrode active material from the positive electrode foil (aluminum foil) made of impurity aluminum (Al) is promoted and separated. A method was proposed.

  For example, the method described in Patent Document 1 is a method for removing a positive electrode active material that peels a positive electrode active material containing a valuable metal constituting a lithium ion battery from a positive electrode substrate made of an aluminum foil, and disassembles the lithium ion battery. The battery disassembled product obtained in this way is immersed in a surfactant solution and stirred to peel the positive electrode active material from the positive electrode substrate.

  Patent Document 2 also shows a peeling procedure (method) using an acidic solution. However, in this method, both aluminum and the positive electrode active material are eluted, and it may be difficult to separate only the positive electrode active material.

  In any of the methods described in the above-described documents, the step of peeling off the positive electrode active material and the step of leaching valuable metals from the positive electrode active material are very complicated treatments. However, it is difficult to say that it is an efficient method. Further, when separating aluminum, valuable metals such as nickel leached into the solution may be separated and removed, resulting in a recovery loss of valuable metals.

JP2012-038572 JP2012-036420

  Therefore, the present invention has been proposed in view of such circumstances, and for example, a sulfuric acid solution is obtained from a defective product generated in a positive electrode material manufacturing process of a lithium ion battery, a positive electrode material taken out from a used lithium ion battery, or the like. A method for separating and removing aluminum capable of effectively and efficiently separating and removing aluminum eluted in a sulfuric acid solution while suppressing recovery loss of the leached valuable metal when using it to leach and collect valuable metal Another object of the present invention is to provide a method for recovering valuable metals from a lithium ion battery to which the method is applied.

  The inventors of the present invention have made extensive studies to achieve the above-described object. As a result, a valuable metal is recovered by adding bicarbonate or carbonate to a solution obtained by leaching the positive electrode material with a sulfuric acid solution (sulfuric acid leachate) and adjusting the pH to a predetermined pH range. The inventors have found that aluminum derived from the eluted positive electrode substrate in the sulfuric acid leachate can be effectively separated and removed while suppressing loss, and the present invention has been completed.

That is, in the method for separating and removing aluminum according to the present invention, a positive electrode material of a lithium ion battery in which a positive electrode active material is fixed to a positive electrode substrate made of an aluminum foil is immersed in a sulfuric acid solution, and nickel or cobalt contained in the positive electrode active material Is a method of separating and removing aluminum eluted in the sulfuric acid solution when leaching and recovering, after the positive electrode material is immersed in the sulfuric acid solution, a bicarbonate or carbonate is added to the sulfuric acid solution. By adjusting the pH to the range of 3.5 to 6.5, the aluminum eluted in the sulfuric acid solution is separated as aluminum hydroxide and filtered while suppressing the coprecipitation of nickel or cobalt .

In addition, the method for recovering valuable metals from a lithium ion battery according to the present invention includes the step of immersing a positive electrode material in which a positive electrode active material is fixed to a positive electrode substrate made of an aluminum foil in a sulfuric acid solution, and nickel or cobalt contained in the positive electrode material. After the leaching of the aluminum, the bicarbonate or carbonate was added to adjust the pH to a range of 3.5 to 6.5, thereby suppressing the coprecipitation of nickel or cobalt, while the aluminum eluted in the sulfuric acid solution was removed. It is characterized by including a step of separating and filtering as aluminum hydroxide.

  Here, at the time of separating and removing aluminum, it is preferable to separate the aluminum hydroxide by adding the hydrogen carbonate or carbonate with the temperature of the sulfuric acid solution maintained at a constant temperature, followed by filtration. Moreover, it is preferable to maintain the temperature of the sulfuric acid solution at a constant temperature in the range of 50 to 90 ° C.

  According to the present invention, it is possible to effectively and efficiently separate and remove the eluted aluminum derived from the positive electrode substrate while suppressing the precipitation of valuable metals such as nickel leached into the sulfuric acid solution. Thereby, when recovering valuable metals such as nickel, it is possible to recover high-purity valuable metals with reduced impurities while effectively suppressing recovery loss of the valuable metals. Moreover, since aluminum can be separated and removed by a very simple method, the cost of the valuable metal recovery process can be reduced without complicated leaching treatment and aluminum removal treatment.

It is a flowchart which shows the flow of the separation / removal method of aluminum.

Hereinafter, a specific embodiment of a method for separating and removing aluminum according to the present invention and a method for recovering valuable metals from a lithium ion battery to which the method is applied (hereinafter referred to as “the present embodiment”) will be described in the following order. Will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.
1. 1. Method for separating and removing aluminum Method for recovering valuable metals from lithium-ion batteries

<1. Method for separating and removing aluminum>
The method for separating and removing aluminum according to the present embodiment includes immersing a positive electrode material, which is a lithium ion battery and having a positive electrode active material fixed to a positive electrode substrate made of an aluminum foil, in a sulfuric acid solution. When leaching and recovering valuable metals such as nickel (N i) and cobalt (C o ) contained, the aluminum derived from the positive electrode substrate eluted in the sulfuric acid solution is effectively and efficiently separated and removed. .

  Specifically, in this method of separating and removing aluminum, after the positive electrode material of a lithium ion battery is immersed in a sulfuric acid solution, a hydrogen carbonate such as sodium hydrogen carbonate or a carbonate such as sodium carbonate is added to the sulfuric acid solution. Adjust to pH 3.5-6.5. Thus, the aluminum eluted in the sulfuric acid solution is separated as aluminum hydroxide and filtered.

  According to such a method, the eluted aluminum derived from the positive electrode substrate can be effectively and efficiently separated and removed while suppressing the precipitation of valuable metals such as nickel leached into the sulfuric acid solution. As a result, valuable metals such as nickel are effectively removed from defective scrap generated in the positive electrode material manufacturing process, positive electrode material taken out from used lithium ion batteries, etc., while effectively preventing recovery loss. Can be collected and recycled effectively. In addition, since aluminum can be separated and recovered by a very simple method, the cost of the valuable metal recovery process can be reduced without the complicated leaching process and aluminum removal process as in the prior art.

  As described above, the positive electrode material of the lithium ion battery to which the method for separating and removing aluminum according to this embodiment is applied is obtained by fixing a positive electrode active material to a positive electrode substrate made of an aluminum foil. Although it does not specifically limit as this positive electrode material, For example, the defective product (manufacturing process scrap) which generate | occur | produced in the manufacturing process of a positive electrode material, the positive electrode material obtained by disassembling a used lithium ion battery, etc. Can be used.

  The positive electrode active material contained in such a positive electrode material contains nickel-cobalt-manganese composite hydroxide, compounds such as lithium cobaltate and lithium manganate. In the present embodiment, valuable metals such as nickel, cobalt, manganese and lithium contained in the compound constituting such a positive electrode active material are leached using a sulfuric acid solution.

  In the leaching treatment, for example, pure water or the like is added to the positive electrode material described above to form a slurry, and a sulfuric acid solution is added to the slurry to immerse the positive electrode material in the sulfuric acid solution. In this leaching treatment, only the positive electrode active material is not separated from the positive electrode material and immersed in the sulfuric acid solution, but is immersed in an aluminum foil constituting the positive electrode substrate. Here, valuable metals contained in the positive electrode active material are effectively leached in a reducing environment. Therefore, by dipping in the sulfuric acid solution in the state of the positive electrode material fixed to the aluminum foil in this way, the reduction action of aluminum (foil) can be used, and the leaching reaction of the positive electrode active material proceeds more effectively. Can be made.

Specifically, this leaching reaction proceeds as shown in the following reaction formula (i). Here, the positive electrode active material is shown as LiNiO ₂ , but is not limited thereto.
6LiNiO ₂ + 2Al + 12H ₂ SO ₄ →
3Li ₂ SO ₄ + 6NiSO ₄ + Al ₂ (SO ₄ ) ₃ + 12H ₂ O (i)

The above leaching reaction is allowed to proceed until there is no generation of hydrogen due to the reducing action of aluminum. Therefore, in an environment where a relatively large amount of aluminum is present, all positive electrode active materials such as LiNiO ₂ are leached.

  Although it does not specifically limit as a sulfuric acid solution used for leaching, It is preferable to use what adjusted the density | concentration so that the pH may be in the range of about 0-3. Also, the amount (input amount) of the positive electrode material with respect to the sulfuric acid solution is not particularly limited, and can be, for example, about 10 to 100 g / l with respect to the sulfuric acid solution.

By the way, in the leaching process described above, a part of aluminum constituting the positive electrode substrate is eluted in the sulfuric acid solution with the reaction due to the reducing action of aluminum (the following formula (ii)). Valuable metals leached into the sulfuric acid solution by the leaching treatment are recovered as sulfides by, for example, sulfidation, etc., but prior to the recovery, the aluminum eluted together with the valuable metals in the sulfuric acid solution is effectively and It is necessary to efficiently separate and remove.
2Al + 3H ₂ SO ₄ → Al ₂ (SO ₄ ) ₃ + 3H ₂ (ii)

Therefore, in the present embodiment, as shown in the flow in FIG. 1, for example, a positive electrode material such as scrap is immersed in a sulfuric acid solution to leach valuable metals, and then a neutralizing agent is added to the sulfuric acid solution. To adjust the pH to a predetermined range. Thus, as shown in the following reaction formula (iii), aluminum eluted in the sulfuric acid solution is precipitated and separated as aluminum hydroxide (Al (OH) ₃ ), and the solution containing the precipitate is filtered.
Al ₂ (SO ₄ ) ₃ + 6NaOH → 2Al (OH) ₃ + 3Na ₂ SO ₄
(Iii)

As the neutralizing agent added to the sulfuric acid solution, it is important to adjust to a predetermined pH using an alkaline hydrogen carbonate or carbonate. Specifically, pH adjustment using sodium salt (NaHCO ₃ , Na ₂ CO ₃ ), potassium salt (KHCO ₃ , K ₂ CO ₃ ), calcium salt (Ca (HCO ₃ ) ₂ , CaCO ₃ ), etc. Is preferred

  Here, as the neutralizing agent, for example, an alkali such as sodium hydroxide may be used, and according to this, aluminum can be effectively converted into a hydroxide. However, aluminum hydroxide produced by adding a neutralizing agent is a compound having a coprecipitation action. When sodium hydroxide or the like is used as a neutralizing agent, valuable metals such as nickel leached into the sulfuric acid solution are used. Co-precipitation is promoted, resulting in a loss of valuable metal recovery. In this respect, coprecipitation of valuable metals leached into the sulfuric acid solution can be suppressed by adding a hydrogen carbonate or carbonate such as sodium hydrogen carbonate or sodium carbonate to the sulfuric acid solution as a neutralizing agent. The recovery loss of valuable metals can be effectively prevented.

  Further, in this method for separating and removing aluminum, it is important to adjust the pH of the sulfuric acid solution to a range of 3.5 to 6.5 by adding the neutralizing agent described above. If the pH is less than 3.5, the eluted aluminum hydroxide is not generated, and the aluminum cannot be separated and removed effectively. On the other hand, when the pH exceeds 6.5, the formation of a hydroxide of nickel leached into the sulfuric acid solution starts, so that nickel coprecipitates with aluminum hydroxide and causes a recovery loss. Therefore, by adding a neutralizing agent and adjusting the pH of the sulfuric acid solution to the range of 3.5 to 6.5, aluminum hydroxide can be effectively generated while suppressing the coprecipitation of nickel. . Moreover, it is particularly preferable that the eluted aluminum can be more effectively separated as a hydroxide by adding a neutralizing agent and adjusting the pH to about 5.5.

  The amount of hydrogen carbonate or carbonate added is not particularly limited as long as the pH of the sulfuric acid solution can be in the above-described range. Further, the addition method is not particularly limited, and for example, a tube dropping method, a spray dropping method, or the like can be used.

  After separating the aluminum eluted in the sulfuric acid solution by adjusting the pH with a neutralizing agent as described above as a precipitate of aluminum hydroxide, the aluminum hydroxide can be removed by filtering the sulfuric acid solution. The filtration method at this time is not particularly limited, and a general method can be used.

  In this method for separating and removing aluminum, the temperature condition of the sulfuric acid solution is not particularly limited, but is preferably about 50 to 90 ° C, more preferably about 80 ° C. When the temperature is lower than 50 ° C., the aluminum hydroxide formed by the addition of the neutralizing agent gels, and the filtration process takes a long time. On the other hand, if it exceeds 90 ° C., the cost for raising the temperature is increased, which is not efficient and the safety is also lowered.

  Moreover, as temperature conditions, it is preferable to maintain the temperature of the sulfuric acid solution at a constant temperature over a series of operations from addition of a neutralizing agent to filtration treatment. Specifically, for example, after the temperature of the sulfuric acid solution is raised to 80 ° C., a hydrogen carbonate or carbonate as a neutralizing agent is added to form a precipitate of aluminum hydroxide, and the temperature at 80 ° C. It is preferable to perform the filtration treatment in a state in which is kept substantially constant. Thus, the filterability can be enhanced by adding bicarbonate or carbonate to separate and filter aluminum hydroxide while maintaining the sulfuric acid solution at a constant temperature. Further, the effect of suppressing the coprecipitation of valuable metals such as nickel leached into the sulfuric acid solution is enhanced, and the recovery loss of the valuable metals can be more effectively prevented.

<2. Method for recovering valuable metals from lithium-ion batteries>
Next, a method for recovering valuable metals from a lithium ion battery to which the above-described method for separating and removing aluminum is applied will be described. The method of recovering the valuable metal is from the positive electrode active material in the positive electrode material constituting the lithium ion battery, a nickel, a method of recovering leached with sulfuric acid solution valuable metals such as cobalt. In the method for recovering valuable metals from the lithium ion battery according to the present embodiment, during the leaching process, the positive electrode active material is immersed in a sulfuric acid solution in a state of a positive electrode material fixed to a positive electrode substrate made of an aluminum foil. Then, reductive leaching is performed using the aluminum reducing action of the positive electrode substrate.

  Specifically, the method for recovering valuable metals from the lithium ion battery includes a leaching step in which the positive electrode material is immersed in a sulfuric acid solution for reduction leaching, an impurity separation and removal step for separating and removing aluminum eluted in the sulfuric acid solution, And a recovery step of recovering valuable metals from the sulfuric acid leachate from which aluminum has been separated and removed. In the present embodiment, a case where valuable metals are recovered from a defective positive electrode material (manufacturing process scrap) generated in the manufacturing process of the positive electrode material will be described as an example.

[Leaching process]
In the leaching step, for example, pure water is added to the positive electrode material in which the positive electrode active material is fixed to the positive electrode substrate made of an aluminum foil to form a slurry, and a sulfuric acid solution is added to the slurry containing the positive electrode material. It is made to immerse in the sulfuric acid solution, and valuable metals, such as nickel, cobalt, manganese, are leached from the positive electrode active material which comprises a positive electrode material.

  Although it does not specifically limit as a sulfuric acid solution to be used, It is preferable to use what adjusted the density | concentration so that the pH may be set to about 0-3. Further, the amount (input amount) of the positive electrode material with respect to the sulfuric acid solution is not particularly limited, and may be, for example, about 10 to 100 g / l with respect to the sulfuric acid solution.

As described above, in the leaching process in this leaching step, reductive leaching is performed using the reducing action of aluminum (foil) constituting the positive electrode substrate immersed in the sulfuric acid solution together with the positive electrode active material. Thus, by utilizing the reducing action of aluminum, the leaching reaction of the positive electrode active material can be more effectively advanced, and the leaching rate of valuable metals can be improved. As described above, this reductive leaching reaction proceeds until the generation of hydrogen due to the reducing action of aluminum disappears. Therefore, in an environment where a relatively large amount of aluminum is present, a positive electrode active material such as LiNiO ₂ is All will be leached.

  In this way, a leaching solution in which valuable metals such as nickel, cobalt, and manganese are leached and a leaching residue made of impurities are obtained by the reduction leaching process in this leaching step. The leaching residue generated at this time can be separated and removed from the leaching solution by performing a filtration treatment or the like.

  On the other hand, the sulfuric acid leaching solution (sulfuric acid solution) obtained by the reductive leaching process in this leaching step is in a state in which a part of aluminum derived from the positive electrode substrate used in the reductive leaching is eluted. The aluminum eluted in this solution becomes an impurity in the recovery process of valuable metals in the subsequent process, and it is necessary to effectively and efficiently separate and remove the eluted aluminum prior to the recovery of valuable metals. It becomes. Therefore, in the present embodiment, the aluminum eluted in the sulfuric acid solution is separated and removed in the impurity separation and removal step of the next step.

[Impurity separation and removal process]
In the impurity separation and removal step, the aluminum eluted in the solution is separated and removed from the sulfuric acid leaching solution obtained by the reduction leaching process in the leaching step. Specifically, hydrogen carbonate or carbonate is added to the sulfuric acid leaching solution to adjust the pH to a range of 3.5 to 6.5 and neutralized, and the eluted aluminum is precipitated into aluminum hydroxide. And the precipitate is removed by filtration.

  The method for separating and removing aluminum in this impurity separation and removal step is the same as that described above, and a description thereof is omitted here.

  By separating and removing aluminum contained in the sulfuric acid leaching solution in this way, aluminum is effectively and efficiently separated and removed while suppressing precipitation (co-precipitation) of valuable metals such as leached nickel. be able to.

[Recovery process]
In the recovery step, valuable metals are recovered from the sulfuric acid leachate obtained by separating and removing aluminum as an impurity in the impurity removal step. Specifically, as the recovery method, for example, a method in which the sulfuric acid leachate is introduced into a reaction vessel and a sulfurization reaction is caused by adding a sulfurizing agent to recover as a mixed nickel / cobalt sulfide is used. Can do. In the following, as a method for recovering valuable metals, a method for recovering valuable metals as sulfides by subjecting the sulfuric acid leachate to sulfidation will be described as a specific example. It is not limited, and a recovery method suitable for the valuable metal to be recovered can be adopted.

  The sulfiding agent used for the sulfiding treatment is not particularly limited, and sodium sulfide, sodium hydrosulfide, alkali sulfide such as hydrogen sulfide gas, or the like can be used.

Specifically, in this sulfiding treatment, nickel ions (or cobalt ions), which are valuable metals contained in the obtained sulfuric acid leachate, are converted into alkali sulfides according to, for example, the following reaction formulas (1), (2), or (3). Sulfide reaction occurs due to sulfidation reaction.
Ni ²⁺ + H ₂ S ⇒ NiS + 2H ⁺ (1)
Ni ²⁺ + NaHS ⇒ NiS + H ⁺ + Na ⁺ (2)
Ni ²⁺ + Na ₂ S ⇒ NiS + 2Na ⁺ (3)

  Addition of the sulfiding agent in the sulfiding step is performed until the ORP in the reaction solution does not fluctuate even if more sulfiding agent is added. The reaction is usually completed in the range of −200 to 400 mV (reference electrode: silver / silver chloride electrode). The pH of the solution used for the sulfurization reaction is about 2 to 4. The temperature of the sulfurization reaction is not particularly limited, but is 0 to 90 ° C, preferably about 25 ° C.

  In particular, in the above reaction formula (1) or (2), an acid is also generated when the reaction proceeds, and the reaction is delayed. For this reason, in order to accelerate and complete the reaction, it is preferable to neutralize the generated acid by adding an alkali such as sodium hydroxide together with the addition of the sulfurizing agent.

  By causing a sulfurization reaction in this way, valuable metals such as nickel and cobalt contained in the positive electrode active material in the positive electrode material of the lithium ion battery are separated and recovered as nickel / cobalt sulfide (sulfurized starch). This can be recycled as a raw material for producing a magnetic material or a positive electrode active material.

  As described above in detail, in the method for recovering valuable metals from the lithium ion battery according to the present embodiment, a positive electrode material including a positive electrode substrate made of aluminum foil and a positive electrode active material fixed to the aluminum foil is treated with a sulfuric acid solution. After leaching the valuable metal contained in the positive electrode active material by immersing in sulfuric acid, the mixture was adjusted to pH 3.5 to 6.5 by adding bicarbonate or carbonate to the sulfuric acid leaching solution to adjust the pH to 3.5 to 6.5. Separating the aluminum eluted in the solution as aluminum hydroxide and filtering.

  According to such a method for recovering valuable metals, it is possible to effectively and efficiently separate and remove the eluted aluminum derived from the positive electrode substrate while suppressing precipitation of valuable metals such as leached nickel. Thus, valuable metals such as nickel can be recovered with high purity while effectively suppressing the recovery loss.

  Moreover, in such a valuable metal recovery method, aluminum can be separated and recovered in a very simple manner, so that the valuable metal recovery process does not require complicated leaching treatment and aluminum removal treatment as in the past. The cost can be reduced.

  In the above description, the case of recovering valuable metals from the positive electrode material scrap using the defective positive electrode material (manufacturing process scrap) generated in the positive electrode material manufacturing process is described as an example. However, it is not limited to this. For example, a positive electrode material disassembled and recovered from a used lithium ion battery may be used. In that case, prior to performing the above-described leaching step, a discharge step of discharging the lithium ion battery and a used lithium ion battery that has been discharged and rendered harmless are crushed and crushed to take out the positive electrode material. A disassembly step and a cleaning step of cleaning the positive electrode material obtained by disassembly can be performed.

  Specifically, in the discharging step, prior to disassembling a used lithium ion battery, the battery is discharged and rendered harmless. Thereby, the danger at the time of dismantling etc. in a post process is eliminated. In this discharge step, for example, a discharge solution such as a sodium sulfate aqueous solution or a sodium chloride aqueous solution is used, and the used lithium ion battery is immersed in the aqueous solution to be discharged.

  Next, in the dismantling process, the used lithium ion battery that has been rendered harmless by discharge is disassembled by crushing and crushing. In the dismantling process, the harmless battery is crushed (disintegrated) using a normal crusher or crusher, and the internal positive electrode material is taken out by cutting the outer can. At this time, the positive electrode material is also preferably cut to an appropriate size.

Next, in the cleaning step, the positive electrode material obtained by disassembling the lithium ion battery is washed with water or alcohol to remove the attached electrolyte and electrolyte. Since the lithium ion battery contains an organic solvent such as ethylene carbonate, propylene carbonate, diethyl carbonate, and dimethyl carbonate and an electrolyte such as lithium hexafluorophosphate (LiPF ₆ ), these are removed in advance. Thereby, it can prevent that an organic component, phosphorus (P), fluorine (F), etc. are mixed as an impurity in the leaching solution in the leaching step in the subsequent step.

  To clean the battery disassembly, water or alcohol is used, and the organic components and the electrolyte are removed by shaking or stirring. As the alcohol, ethanol, methanol, isopropyl alcohol, or a mixture thereof is used. Carbonates are generally insoluble in water, but the electrolyte component, ethylene carbonate, is arbitrarily soluble in water, and other organic components have some solubility in water, so they can be washed with water. is there. This washing is preferably repeated a plurality of times, whereby phosphorus, fluorine and the like derived from the organic components and electrolyte can be removed to the extent that they do not affect the subsequent steps.

  Examples of the present invention will be described below in comparison with comparative examples. In addition, this invention is not limited by these Examples.

[Example 1]
As a raw material, a defective product (scrap) of the positive electrode material generated in the manufacturing process of the positive electrode component of the lithium ion battery was used. This positive electrode material is obtained by applying a positive electrode active material made of Ni—Co—Mn oxide to an Al plate which is a positive electrode substrate.

First, the positive electrode material was immersed in an H ₂ SO ₄ solution in order to leach out valuable metals Ni, Co, and Mn contained in the positive electrode active material included in the defective positive electrode material. Next, a NaHCO ₃ solution having a concentration of 200 g / l as a neutralizing agent was supplied to the obtained sulfuric acid leaching solution through a supply tube until the pH of the sulfuric acid leaching solution became 5.5, and the solution was stirred with a stirrer. . Thereafter, when the pH of the sulfuric acid solution reached 5.5, the supply of the neutralizing agent was stopped, and the stirring by the stirrer was also stopped. In addition, as temperature conditions, the temperature of the sulfuric acid solution was gradually raised from room temperature to 80 ° C. (room temperature → 80 ° C.) as the reaction proceeded in the neutralization treatment before the addition of the neutralizing agent.

  The obtained filtrate after neutralization treatment (neutralization final solution) was subjected to suction filtration to obtain an aluminum hydroxide starch. When the composition of the filtrate after the neutralization treatment was analyzed by ICP emission analysis, it was Ni: 19 g / l, Co: 22 g / l, Mn: 18 g / l, Al: 0.002 g / l. Compared with the composition of the neutralization starting solution before neutralization (Ni: 31 g / l, Co: 31 g / l, Mn: 25 g / l, Al: 18 g / l), the aluminum content in the sulfuric acid leachate is effectively reduced. I understood that I was able to do it.

  Moreover, when the composition of the obtained neutralized starch (aluminum hydroxide starch) was analyzed by ICP emission analysis, Ni: 4.8%, Co: 1.2%, Mn: 0.37%, Al: 18%. From this analysis value, the ratio of Ni loss to neutralized starch was calculated to be 14.8%. The filtration time for the neutralized starch took 1 day.

[Example 2]
In Example 2, Na ₂ CO ₃ having a concentration of 280 g / l was used as the neutralizing agent, and the temperature condition was maintained at a constant temperature of 80 ° C. from before the addition of the neutralizing agent to during the neutralization treatment. This was carried out in the same manner as in Example 1.

  As a result, the obtained filtrate (neutralization final solution) after neutralization was suction filtered to obtain an aluminum hydroxide starch. When the composition of the filtrate after the neutralization treatment was analyzed, it was Ni: 29 g / l, Co: 30 g / l, Mn: 26 g / l, Al: 0.13 g / l. Compared with the composition of the neutralization starting solution before neutralization (Ni: 31 g / l, Co: 31 g / l, Mn: 25 g / l, Al: 18 g / l), the aluminum content in the sulfuric acid leachate is effectively reduced. I understood that I was able to do it.

  Further, the composition of the obtained neutralized starch (aluminum hydroxide starch) was analyzed. As a result, Ni was 2.7%, Co was 1.1%, Mn was 0.24%, and Al was 19%. It was. From this analysis value, the ratio of Ni loss to neutralized starch was calculated to be 8.2%. Moreover, the filtration time of the neutralized starch was 38 minutes, and the filterability was improved as compared with Example 1.

[Comparative Example 1]
In Comparative Example 1, Example 8 was used except that NaOH with a concentration of 8 g / l was used as the neutralizing agent, and the temperature condition was maintained at a constant temperature of 80 ° C. from before the addition of the neutralizing agent to during the neutralization treatment. 1 was performed.

  As a result, the obtained filtrate (neutralization final solution) after neutralization was suction filtered to obtain an aluminum hydroxide starch. When the composition of the filtrate after the neutralization treatment was analyzed, it was Ni: 20 g / l, Co: 23 g / l, Mn: 20 g / l, Al: 0.019 g / l. Compared with the composition of the neutralization starting solution before the neutralization treatment (Ni: 29 g / l, Co: 28 g / l, Mn: 20 g / l, Al: 17 g / l), it can be seen that aluminum in the sulfuric acid leachate can be reduced. It was.

  However, the composition of the obtained neutralized starch (aluminum hydroxide starch) was analyzed. As a result, Ni was 6.2%, Co was 2.7%, Mn was 0.28%, and Al was 18%. When the ratio of Ni loss to the neutralized starch was calculated, it was 21.2%, and the amount of Ni loss was significantly increased as compared with the Examples.

[Comparative Example 2]
Comparative Example 2 was the same as Example 1 except that NaOH with a concentration of 8 g / l was used as the neutralizing agent, and the temperature condition was maintained at room temperature from before the addition of the neutralizing agent to during the neutralization treatment. I went.

  As a result, the obtained filtrate (neutralization final solution) after neutralization was suction filtered to obtain an aluminum hydroxide starch. When the composition of the filtrate after the neutralization treatment was analyzed, it was Ni: 20 g / l, Co: 21 g / l, Mn: 20 g / l, Al: 0.029 g / l. Compared with the composition of the neutralization starting solution before neutralization treatment (Ni: 24 g / l, Co: 24 g / l, Mn: 20.6 g / l, Al: 17.4 g / l), the aluminum in the sulfuric acid leachate It was found that it can be reduced.

  However, the composition of the obtained neutralized starch (aluminum hydroxide starch) was analyzed. As a result, Ni was 4.6%, Co: 2.7%, Mn: 0.35%, and Al: 16%. When the ratio of Ni loss to the neutralized starch was calculated, it was 19.5%, and the amount of Ni loss was significantly increased as compared with the Examples.

  Table 1 below collectively shows the processing conditions, the filtration time, and the analysis value of the Ni loss amount of the above-described Examples and Comparative Examples.

  As described above, a leaching treatment is performed on a positive electrode material including a positive electrode substrate made of an aluminum foil and a positive electrode active material using a sulfuric acid solution, and the obtained leachate is a hydrogen carbonate salt such as sodium hydrogen carbonate or carbonic acid. By adding a carbonate such as sodium as a neutralizing agent and adjusting to a predetermined pH, the eluted aluminum can be effectively and efficiently prevented while losing valuable metals such as nickel contained in the positive electrode active material. It was found that it can be separated and removed.

  In particular, by adding and reacting with a neutralizing agent while maintaining the temperature of the sulfuric acid solution at a constant temperature, the filterability of the neutralized starch is improved and the loss of valuable metals such as nickel is more effective. It was found that it can be reduced.

Claims (6)

When a positive electrode material of a lithium ion battery in which a positive electrode active material is fixed to a positive electrode substrate made of aluminum foil is immersed in a sulfuric acid solution and nickel or cobalt contained in the positive electrode active material is leached and recovered, it elutes into the sulfuric acid solution. A method for separating and removing aluminum,
After immersing the positive electrode material in a sulfuric acid solution, by adding a hydrogen carbonate to the sulfuric acid solution and adjusting the pH to a range of 3.5 to 6.5, while suppressing coprecipitation of nickel or cobalt, A method for separating and removing aluminum, wherein aluminum eluted in a sulfuric acid solution is separated as aluminum hydroxide and filtered. When a positive electrode material of a lithium ion battery in which a positive electrode active material is fixed to a positive electrode substrate made of aluminum foil is immersed in a sulfuric acid solution and nickel or cobalt contained in the positive electrode active material is leached and recovered, it elutes into the sulfuric acid solution. A method for separating and removing aluminum,
After immersing the positive electrode material in a sulfuric acid solution, the sulfuric acid solution is adjusted to pH 3.5 to 6.5 by adding carbonate to the sulfuric acid solution while suppressing the coprecipitation of nickel or cobalt. A method for separating and removing aluminum, wherein aluminum eluted in a solution is separated as aluminum hydroxide and filtered.   3. The aluminum according to claim 1, wherein the aluminum hydroxide is separated and filtered while the addition is performed while maintaining the temperature of the sulfuric acid solution at a constant temperature within a range of 50 to 90 ° C. 3. Separation removal method. In a method for recovering valuable metals for recovering nickel or cobalt from a lithium ion battery,
A positive electrode material in which a positive electrode active material is fixed to a positive electrode substrate made of an aluminum foil is immersed in a sulfuric acid solution, and nickel or cobalt contained in the positive electrode material is leached, and then a bicarbonate or carbonate is added to adjust the pH to 3. Lithium comprising a step of separating and filtering aluminum eluted in the sulfuric acid solution as aluminum hydroxide while suppressing coprecipitation of nickel or cobalt by adjusting to a range of 5 to 6.5 A method for recovering valuable metals from ion batteries.   5. The lithium ion battery according to claim 4, wherein the addition is performed to separate and filter aluminum hydroxide in a state where the temperature of the sulfuric acid solution is maintained at a constant temperature in a range of 50 to 90 ° C. 6. For recovering valuable metals from sewage. The method for separating and removing aluminum according to claim 1, wherein the bicarbonate is added to adjust the pH to a range of 5.5 to 6.5.

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